LYSINS 



163 



3. Human Erythrocytes Red blood cells are obtained from a 

 normal individual, washed thoroughly with salt solution, and made 

 up as a 1 per cent, suspension in salt solution. 1 c.c. of the suspension 

 is used in the test. 



4. Antigen The acetone-insoluble antigen is used. 



5. Patient's Serum Obtained fresh, from 2 to 5 c.c. of blood. It 

 is used unheated. 



6. Known syphilitic serum. 



7. Known normal (non-syphilitic) serum. 

 The test is performed as follows: 



Mix and incubate one hour in water-bath at 37 C. Remove and add 2 units hemolysin to each 

 tube and incubate in water-bath for one hour. Tubes 1, 3, 5, 6 and 7 should show complete hemo- 

 lysis. Tube 4 should show no hemolysis (positive control). If such be the case the reagents are 

 correctly adjusted and a reading of Tube 2 will be positive (no hemolysis) or negative (hemolysis). 



A further simplification of the method has been made by Noguchi. 

 The hemolysin and antigen respectively may be absorbed on squares 

 of filter paper, dried, and standardized. In this state they retain 

 their potency for several weeks. In practice the squares of paper are 

 added directly to the tubes, thus saving much time. 



Complement-fixation in Bacterial Infections. Preparation of Antigen 

 from Bacteria. Experience has clearly shown that bacterial antigens 

 should be polyvalent prepared by mixing in equal amounts, several 

 strains of the same organism. The antigen may be prepared in one 

 of several ways. 



The simplest method is to wash off bacteria from agar slants,, at 

 the period of maximum growth, with salt solution and shake thoroughly 

 to make a uniform suspension. A small amount of phenol (0.5 per 

 cent.) and 3 per cent, glycerin are then added and the whole sterilized 

 at 56 to 60 C. for one hour. Relatively more of the proteins of the 

 bacterial cell may be obtained in solution if the bacterial emulsion 

 is shaken in a shaking machine with sterile, sharp quartz-sand for 

 twenty-four hours: filtration through coarse Berkefeld filters removes 



1 Forty per cent, solution of fresh guinea-pig serum in salt solution. 



